1. Field of the Invention
The present invention relates to an oil pump structure for stabilizing discharge pressure of an oil pump of a variable-capacity type, which is used in a vehicle engine, or the like.
2. Description of the Related Art
As oil pumps for automobile engines, there are variable-capacity oil pumps in which the discharge amount can be increased and decreased. Among these, there are pumps wherein the operation of varying the discharge amount is performed by hydraulic means. A specific example of a pump of this kind is disclosed in Japanese Patent Application Publication No. 2012-145095. In Japanese Patent Application Publication No. 2012-145095, as a means for varying the discharge amount, an adjustment ring (14) is moved, thereby causing the pump capacity to increase or decrease. A hydraulic valve is used as means for moving the adjustment ring (14).